434 THE CANADIAN NATURALIST. [Tol. vi. 



discvs, all of which have been described by Prof. Hartt. It may 

 here be noticed that in 1862, Prof. Bell found in the black 

 shales of the Dartmouth valley, in Gaspe, a single specimen of a 

 large trilobite, which, according to Mr. Billings, closely resembles 

 Paradoxides Hurlani, but from its imperfectly preserved condi- 

 tion cannot certainly be identified with it. [Geol. Canada, 882]. 



The geological examinations of Mr. Alexander Murray in 

 Newfoundland since 1865, have shown that the south-eastern 

 part of that island contains a great volume of Cambrian rocks, 

 estimated by him at about 6,000 feet in all. No traces of the 

 Upper Cambrian or second fauna have been detected among 

 these, but some portions contain the Paradoxides already men- 

 tioned, while others yield the fauna which Mr. Billings has 

 called Lower Potsdam. This name was first given in an ap- 

 pendix (prepared by Sir W. E. Logan,) to Mr. Murray's report 

 on Newfoundland for 1865, published in 1866 [page 46 ; see 

 also Report of the Geol. Survey of Canada for 1866, page 236.] 

 The Lower Potsdam was there assigned a place above the Par- 

 adoxides beds of the region, which were called the St. John 

 group, — the fossiliferous strata of St. John, New Brunswick, 

 being referred to the same horizon ; which corresponds to the 

 Menevian of Wales, now recognized as the summit of the Lower 

 Cambrian. The succession of the rocks containing these two 

 faunas in south-eastern Newfoundland is not yet clear ; the 

 Lower Potsdam fauna is regarded by Mr. Billings as identical 

 with that found on the strait of Bellisle, at Bic, (on the south 

 shore of the river St. Lawrence, below Quebec,) at Georgia, 

 Vermont, and at Troy, New York ; but in none of these other 

 localities is it as yet known to be accompanied by a Menevian 

 fauna. The trilobites hitherto described from these rocks belong 

 to the genera Olenellus, Conocoryphe and Agnostus ; neither 

 Paradoxides, which characterizes the Menevian and the under- 

 lying Harlech beds in Wales, nor Olenus, which there abounds 

 ■ in the rocks immediately above this horizon, having as yet been 

 described as occurring in the Lower Potsdam of Mr, Billings. 

 Future discoveries may perhaps assign it a place below instead 

 of above the Menevian horizon. 



The characteristic Menevian fauna in and near St. John, New 

 Brunswick, is found in a band of about 150 feet, towards the 

 base of a series of nearly vertical sandstones and argillites, 

 underlaid by conglomerates, and resting upon crystalline schists. 



